Grade students on weight: French diet guru

France's top diet guru Pierre Dukan is urging the government to grade students on their weight in a bid to curb growing obesity.

In a book to be published on Thursday, Dukan suggests that students in their last two years of high school be awarded extra marks if they manage to maintain an acceptable Body Mass Index (BMI), a measure of body fat based on height and weight.

"Obesity is a real public health problem that is rarely - if at all - taken into account by politicians," Dukan told newspaper Le Parisien ahead of the book's launch.

Dukan said his education plan would be "a good way to sensitise teenagers to the need for a balanced diet."

He denied it would punish overweight children, saying: "There is nothing wrong with educating children about nutrition. This will not change anything for those who do not need to lose weight. For the others, it will motivate them."

The book is entitled An Open Letter to the Future President and is being released ahead of a presidential election in France in April.

France has taken a series of measures to fight what experts say is increasing obesity in the country, including the introduction on January 1 of a tax on sugary drinks.

France however remains among the lowest-ranked European countries in terms of obesity, with 12.7 per cent of women and 11.7 per cent of men considered obese, according to a study released by the European Union's statistics agency in November.

The top rankings went to British women, 23.9 per cent of whom are considered obese, and Maltese men, 24.7 per cent of whom are obese.

Dukan promotes a high-protein diet that has seen him sell millions of books and win over a slew of celebrity followers.